Carton blank



Nov. 5, 1968 R. A. CARLE 3,409,204

- CARTON BLANK Filed Aug. 1. 1966 2 Sheets-Sheet 1 CO 8 g E :2 M g c: oc: 9

lNl/E'NTOR R. A. CARLE ATTORNEYS Nov. 5, 1968 R A. CARLE 3,409,204

CARTON BLANK Filed Aug. 1. 1966 2 Sheets-Sheet 2 United States Patent3,409,204 a CARTON BLANK Robert A. Carle, Bartlesville, Okla, assignort0 Phillips Petroleum Compay, a corporation of Delaware Filed Aug. 1,1966, Ser. No. 569,410 11 Claims. (Cl. 22936) ABSTRACT OF THE DISCLOSUREA carton blank formed from a single sheet of material adapted to befolded into a self-supporting box without the use of external fastenerscomprises a bottom panel, side panels, interior, middle and exterior endpanels, and a top panel provided with a tab for maintaining the toppanel in closed position.

This invention relates to a blank suitable for folding into a box-likecontainer. In one aspect, it relates to a blank of one-piececonstruction suitable for forming a carton. In another aspect, itrelates to a blank which can be folded and interlocked to form a cartonwithout the use of staples, glue, or other fastenings. In anotheraspect, it relates to a blank which can be folded to form a carton, usedfor carrying articles, and knocked down to a flat blank again a greatplurality of times without damage to the blank. In still another aspect,it relates to a carton formed from a single blank of thermoplasticmaterial. In still another aspect, it relates to a knocked-down cratesuitable for repeated use in transporting perishable goods such as eggs.

Box-like containers are generally supplied to manufacturers andpackagers as fiat blanks which can be assembled at the point of use.Generally, this assembly requires the use of glue, staples, or otherfastening devices, although blanks which interlock without fasteningdevices are also known. A blank which can be interlocked without the useof external fastening devices or tools has the obvious advantage ofbeing capable of being assembled at any point in the field where toolsor fastening devices may not be readily available. Furthermore, boxeswhich are held together by interlocking parts rather than externalfasteners can generally be knocked down to a completely flat blank afteruse. This is a distinct advantage for reusable containers which areshipped to the user flat, assembled and packed by him, and shipped tothe consignee of the goods who can remove the articles and return thecarton to the supplier in a completely knocked-down, fiat condition.When such reuse is contemplated, one-piece construction of the carton isextremely desirable.

It is therefore an object of this invention to provide a blank suitablefor folding into a container withoutexternal fasteners. It is a furtherobject of this invention to provide a reusable container which can bereadily knocked down to a completely fiat blank. It is a further objectof this invention to provide a sturdy container suitable for a greatnumber of reuses. It is a further object of this invention to provide areusable egg carton.

Other aspects, objects and the several advantages of this this inventionare apparent to one skilled in the art from a study of this disclosure,drawings and the appended claims.

According to the invention, I provide a blank of a single piece ofmaterial, having integrally formed hinges, which folds and interlocks toform a carton by means of co-acting tabs and slots, and which requiresno external fasteners. In a preferred embodiment, the carton is formedof synthetic thermoplastic material.

The novel features of my invention can be readily seen by reference tothe appended drawings. FIGURE 1 is a plan view of one embodiment of theblank of my inven- 3,409,204 Patented Nov. 5, 1968 tion. FIGURE 2 is aplan view of a different embodiment. FIGURE 3 is a cross-section view ofthe tabs provided on the blank. FIGURE 4 is a cross-section of anintegral hinge formed when a thermoplastic material is used in the blankof my invention. FIGURE 5 is a cross-sectional view of a hand holeprovided on the blank of thermoplastic material. FIGURE 6 is across-section of a modified hand hole provided on my carton.

Referring now to FIGURE 1, the blank of my invention'has a bottompanel 1. Interior end panels 2 are attached to bottom panel 1 alonglongitudinal fold line 3. Side panels 4'are attached to bottom panel 1along transverse fold lines 6. One of side panels 4 has attached theretoalong longitudinal fold lines middle end panels 7. The other of sidepanels 4 has attached thereto along longitudinal fold lines exterior endpanels 8. In a preferred em bodiment, end panels 2, 7 and 8' are allprovided with hand holes, as will be discussed more fully below.

Attached to one of side panels 4 along a transverse fold line 9 is aninner top panel 11. In this embodiment, inner top panel 11 is providedwith an extension 12 forming a tab 13. Upon assembly of the box, tab 13will fit through slots 14 and 15 on the side panel opposite the one towhich the interior top panel is attached, thus holding the inner toppanel in position over the contents of the assembled container.Oppositely disposed from inner top panel 11 is outer top panel 16, whichis attached along longitudinal fold line 17 to side panel 4. This outertop panel is provided with at least one tab 18 which, upon assembly ofthe carton, will be inserted into an oppositely disposed slot 19. In theembodiment shown, slot 19 is disposed on transverse fold line 9.However, this slot could be disposed either entirely on inner top panel11, or on the side panel opposite the one to which the outer top panelis attached.

Exterior end panels 8 are provided with at least one tab 21. Uponassembly of the carton, tab 21 will be inserted into slot 22 on middleend panel 7. If desired, corresponding slots could be supplied ininterior end panel 2, in which case tab 21 would be inserted through theslots on both the interior and middle end panels, locking the threepanels together.

In the embodiment shown in FIGURE 1, exterior end panels 8 are providedwith subpanels 23 joined along transverse fold lines 24. These subpanelsare optional, but aid in keeping dust and water from entering theassembled carton around the top edges, Upon assembly, subpanels 23 wouldbe folded over the contents before inner top panel 11 is folded down andlocked into position.

In order to aid in the interlocking of the carton parts, tabs 13 and 18are conveniently corrugated, as is shown in FIGURE 3. The corrugationsmake an angle of approximately 45 with the horizontal. The size of thecorrugations will depend upon the size of the container. In the case ofa container designed to hold from 24 to 30 dozen eggs, it has been foundthat corrugations of approximately inch distance between peak and valleyare satisfactory.

Tabs 21 can either be corrugated, or can be provided with transversefold line 26 to allow the tab to be securely interlocked in slot 22.

End panels 2, 7, and 8 can be provided with hand holes which come intoregistration when the blank is assembled into a carton. Although thehand holes can be completely out out, it is preferred that the materialcut from exterior end panel 8 be only partially severed, and remainattached to the end panel along fold line 27. After the three hand holeshave been brought into registration, this dependent material can befolded up inside of end panels 2 and 7, thus holding the three endpanels together. If desired, material cut from the hand hole in middleend panel 7 can also be only partially severed so that there 3 are twothickness of materal folded up inside interior end panel 2 when thecarton is assembled.

If desired, raised buttons 28 can be provided on the top of outer toppanel 16, and corresponding holes 29 cut in bottom panel 1 to allowinterlocking of a plurality of cartons when they are stacked one uponanother. Alternately, the outer surfaces of bottom panel 1 and outer toppanel 16 can be somewhat roughened or knurled to minimize slippage whenthe cartons are stacked on top of each other.

A modification of the blank of my invention is shown in FIGURE 2. Inthis modification, bottom panel 41 has attached thereto interior endpanels 42 along longitudinal fold lines 43. Side panels 44 are attachedto bottom panel 41 along transverse fold lines 46. Middle end panels 47are attached to one of side panels 44, and exterior end panels 48 areattached to the other side panel 44. In this embodiment, inner top panel51 is abbreviated, and contains no means for interlocking with theopposite side panel, as is the case in the embodiment shown in FIG- URE1.

Outer top panel 56 is provided with corrugated tabs 58, which areadapted for insertion into slots 59.

As shown in this embodiment, the material cut from the hand hole inexterior end panel 48 can remain partially attached to the end panelalong the bottom edge of the hand hole, as well as along the top edge,as shown in the previous embodiment.

A slightly different configuration of exterior end panel tabs 61 isshown in this modification than is shown in FIGURE 1, but it ismechanically equivalent to the embodiment of FIGURE 1 in this respect.

The carton of my invention can be manufactured from any material whichhas sufiicient rigidity to be formed into a self-supporting carton ofthe size desired. The carton can thus be of cardboard, coated cardboard,metal, or plastic. When the blank is formed of cardboard, metal, orother non-resilient material, the various transverse and longitudinalfold lines illustrated on the drawings will generally be formed bycreasing the material as is known in the art.

In a preferred embodiment, the carton of my invention is made of asynthetic thermoplastic material. Because of their strength andtoughness, cartons made of thermoplastic materials have been shown to becapable of making more than 100 round trips, whereas cardboard cartonsare suitable for only about trips. Furthermore, the thermoplasticcartons can be washed if they become soiled. They can be sterilized ifdesired. Furthermore, when the perishable goods are shipped underrefrigeration, cartons made of thermoplastic material will not beweakened because of the dampness inherent in the refrigeration process,as will cardboard cartons.

Any synthetic plastic material can be used to form the blank of myinvention, provided it has sufiicient flexibility to form a hingestructure, as will be discussed below, and has sufficient rigidity toprovide a self-supporting box. Impact polystyrene, plasticizedpolyvinylchloride containing small amounts of filler, and polyolefinshave been proven satisfactory. The preferred pastics are polymers andcopolymers of ethylene, propylene and butene. The materials which arecurrently most preferred are polypropylene and high density polyethylene(0.95-0.96 density). The polymer can contain pigments, anti-oxidants,ultra-violet light stabilizers, destatisizing agents, and the like.

In one embodiment, a strong, light-weight carton is made by forming theblank from a foamed plastic material. Foamed polyethylene or foamedpolypropylene are satisfactory, as is foamed semi-flexible polyurethane.Laminates can also be used in the process of my invention, including asandwich-type construction having solid skin and a foam core.

The sheet stock for the blank is formed by any known means. In the caseof thermoplastics, extrusion is ordinarily used, although calendering isalso possible. The

blank is normally die cut from sheet stock on either a flat orcylindrical die.

The thickness of the material will be dependent upon the size of thecarton, and the weight which it is designed to carry. For cartonssuitable for transporting 24 or 30 dozen eggs, the blank can be cut fromsheet material of ,4 inch thickness. For cartons of this size, no centerdivider is needed, as is needed in cardboard cartons of equivalent size.When foamed sheet stock is used, the thickness of the material may haveto be increased in order to gain additional strength.

When the blank is made of thermoplastic material, the various transverseand longitudinal fold lines which have been discussed in connection withthe drawings will comprise integral cold formed hinge structure. Theseintegral hinges are formed by cold rolling the thermoplastic along aline in order to thin out the material. As some orientation of thematerial generally takes place in this thinning, the hinge structure isquite strong. The hinges will generally be formed at the same time thatthe blank is die cut from sheet stock.

FIGURE 4 shows a cross-section of a hinge structure. As seen in thisdrawing, the walls of the carton 62 are thinned down at the hinge 63 toa thickness of approximately 25 percent of their original thickness. Asa matter of hinge design, the Width of the hinge is generallyapproximately equal to the thickness of the material.

In forming hinge structures for the depending material at the handholes, the hinge is required to make a 180 bend, rather than just abend, as is shown in FIG- URE 5, which is taken along section 5-5 ofFIGURE 1. The hinge is therefore made of double width. FIGURE 5 showsexterior end panel 8 having dependent material 64 cut from the hand holejoined thereto by double hinge width 66. In assembled position, theupper edges of hand holes on end panels 2 and 7 will fit between outerwall 8 and material 64.

An alternate hinge arrangement for the hand hole area is shown in FIGURE6. In this modification, two hinges are formed with a space betweenthem, rather than forming a single double width hinge. This type of handhole arrangement has been used in conjunction with the blank shown inFIGURE 2, and is the currently preferred embodiment. In this drawing,exterior end wall 48 is attached through hinge 67 to web 68. Attached toweb 68 is a second hinge 69, attaching flap 70.

As has been indicated, the cartons formed according to this inventionhave found utility for shipping of eggs. A carton suitable for holding24 dozen eggs is 12 x 24 x 11%; inches, and one for transporting 30dozen eggs is 12 x 24 x 12% inches. Since the cartons can be readilycleaned, are not adversely affected by dampness or refrigeration, andcan be knocked down completely flat for return trips, they have beenextremely successful in transporting eggs from the chicken farm to theprocesser. Cartons which have been most successful in this applicationhave been made from a homopolymer of ethylene having a density of 0.960and a melt index of 0.1, and sold under the Trademark Marlex 6001. Thecartons are also expected to find utility in transporting poultry andother perishable goods, as well as other articles such as bottled orcanned drinks.

If desired, the cartons of this invention can be provided with randomholes cut in all sides of the cartons both for ventilation and forlightening of the cartons.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure, the drawings and the appended claims to theinvention, the essence of which is a one-piece blank suitable forfolding into a carton and interlocking by means of tabs and slots toform a rigid container without use of external fasteners.

I claim:

1. A blank formed from a single sheet of material adapted to be foldedinto a self-supporting box without use of external fastener comprising:

(a) a bottom panel (b) interior end panels attached to each end of saidbottom panel along longitudinal fold lines;

(0) side panels attached to said bottom panel along transverse foldlines;

(d) middle end panels attached to one of said side panels alonglongitudinal fold lines;

(e) at least one transversely disposed slot in each said middle endpanel adjacent said side panel;

(f) exterior end panels attached to the other of said side panels alonglongitudinal fold lines;

(g) at least one tab on each said exterior end panel remote from saidother side panel and adapted for insertion into said slot in said middleend panel;

(h) an inner top panel attached to one of said side panels along atransverse fold line;

(i) an outer top panel attached along a transverse fold line to the sidepanel opposite the one to which said inner top panel is attached; and

(j) at least one tab on the edge of said outer top panel opposite thetransverse fold line attaching said outer top panel to said side panel,said tab adapted for inseition into a slot provided whereby said outertop panel is maintained in covering relation to the assembled box.

2. The blank of claim 1 wherein said inner top panel has an extensionforming a tab adapted for insertion into a slot provided on the sidepanel opposite that to which said inner top panel is attached.

3. The blank of claim 1 wherein said slot provided for insertion of thetab on said outer top panel is on said inner top panel.

4. The blank of claim 1 wherein said slot provided for insertion of thetab on said outer top panel is on the side panel opposite that to whichthe said outer top panel is attached.

5. The blank of claim 1 wherein said slot provided for insertion of thetab on said outer top panel is on the fold line joining said inner toppanel to the side panel.

6. The blank of claim 1 wherein said tabs are corrugated.

7. The blankof claim 1 wherein said exterior end panels have subpanelsjoined thereto along transverse fold lines, said subpanels adapted tofold at least partially over the contents of the assembled box inside ofsaid interior top panel.

8. The blank of claim 1 wherein said material is thermoplastic and' saidfold lines comprise integrally formed hinges.

9. The blank of claim 8 wherein said thermoplastic is selected fromimpact polystyrene, polyvinylchloride, and polymers and copolymers ofethylene, propylene, and butene.

10. The blank of claim 8 wherein said thermoplastic is foamed.

11. The blank of claim 1 wherein said interior, middle and exterior endpanels have hand holes formed therein, the exterior end panels having aflap of material dependent from one edge of its hand hole, said flapadapted to fold over the corresponding edges of the hand holes in saidinterior and said middle panels.

References Cited UNITED STATES PATENTS 2,741,415 4/1956 Meitzen 229362,833,459 5/1958 Greene 22935 3,165,253 l/1965 Adams 229-33 3,222,43712/ 1965 Schilling.

3,288,349 11/1966 Palmer 229-3.5

DONALD F. NORTON, Primary Examiner.

